A rotatable bezel is provided in the case of a so-called diver's watch, aiming for allowing users to easily know how much time is left for diving or other purposes. The bezel is rotatable to a certain position and then maintains the position. However, the bezel may be easily moved from the position when hit by an obstacle, for example.
To prevent such an unintentional motion of the bezel, a rotation preventing (lock) mechanism has been proposed for allowing the bezel to rotate by rotational operation and restricting the rotation of the bezel in non-rotational operation (see Japanese Laid-Open Patent Applications No. 2008-128880 and No. 2010-185833). According to this mechanism, a lock element is generally engaged with the bezel to limit the rotation of the bezel when the bezel is not operated. On the other hand, the lock element and the bezel are disengaged from each other by pressing a push-button or an unlock button to allow the bezel to rotate when the bezel is operated.